The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
U.S. Pat. No. 4,849,185 A describes an apparatus for effecting high temperature catalytic conversion treatment of exhaust gases flowing in a large volume exhaust path including a plurality of separate catalyst panel assemblies, and a panel support assembly arranged to be mounted within the exhaust path and to separately removably support each of the plurality of catalyst panel assemblies so that high temperature exhaust gases within the exhaust path will flow therethrough in operation and each panel assembly can be conveniently serviced by simple removal. The panel support assembly includes an outer ambient temperature peripheral frame structure, an inner high temperature peripheral frame structure mounted within the outer peripheral frame structure for temperature responsive expansion and contraction with respect thereto, and an expansible and contractible high temperature resistant peripheral seal assembly between the inner and outer peripheral frame structures for maintaining a flow preventing seal therebetween. Each catalyst panel assembly is supported by an arrangement which includes doors openable to permit the catalyst panel assemblies to be removed. Each panel assembly includes a guarded high temperature resistant peripheral seal assembly for insuring that the flow of high temperature exhaust gases within the exhaust path is solely through the catalyst passages thereof.
U.S. Pat. No. 6,089,347 A describes a muffler having a casing, an inlet opening and an outlet opening. An initial partition forms an expansion chamber. The casing has mounted and formed therein a partition array that includes a divider partition, a first intermediate partition, and a second intermediate partition. Partition array is positioned in a main sound attenuation chamber. A collector partition having a collector opening is positioned between array and opening. A pre-outlet chamber is formed by collector partition prior to outlet.
U.S. Pat. No. 7,281,606 B2 describes an exhaust sound and emission control systems for reducing sound and noxious emissions from an automotive exhaust. The system may have an exhaust resonator having one or more catalytic converter elements in combination therewith in a single device. Alternatively, the system may have multiple angularly disposed chambers therein, with a series of swept baffles or guides in one of the chambers, thereby combining resonator and muffler functions in a single device. In another alternative, the system has a series of longitudinal tubes therein in combination with a series of V-shaped guides or vanes, combining catalytic converter, muffler, and resonator functions in a single device. The various elements of the different embodiments, e.g. catalytic converter element(s), double wall shell, perforated tubes and multiple flow paths, interconnecting crossover tubes, etc., may be combined with one another as practicable.